1. Technical Field
The present invention is directed to an improved method and system for increasing network capacity in a Global System for Mobile Communications (hereinafter GSM) networks and in particular for overall system capacity improvement by reducing the number of home location register and visitor location register queries. Still more particularly the present invention relates to an improved method and system that allows the routing of calls from a gateway mobile switching center to a visiting mobile switching center without home location register and visitor location register queries.
2. Description of the Related Art
In telecommunications, based on a Global System for Mobile Communications xe2x80x9cGSMxe2x80x9d standard, a land-to-mobile phone call consists of two-phases; a setup phase and a user communication phase. During the call setup phase, signaling messages are exchanged between a mobile terminal and a network through a dedicated signaling channel. Currently, the land-to-mobile GSM call setup procedure requires the interrogation every time by a gateway mobile switching center GMSC to a remote home location register (referred to as HLR) and then to a visitor location register (referred to as VLR) located at a visiting mobile switching center for the network to set up a call to the mobile terminal. Having to continuously interrogate the HLR and visiting mobile switching center (hereinafter the MSC) results in significant processing overhead at the GMSC, HLR and visiting MSC. This increases the signaling traffic load, as well as call setup delay.
Therefore, a need exists to increase network efficiency and improve the grade of service by reducing the HLR/MSC signal-processing load. Capacity improvement can be obtained by reducing the number of HLR/VLR queries. In view of the above, it should be apparent that a method and system that allows the routing of calls from the GMSC to the MSC without HLR and VLR queries would be highly desirable. The present invention solves this problem in a new and unique manner that has not been part of the art previously.
It is therefore one object of the present invention to provide an improved method for call setups for GSM networks and in particular for overall system capacity improvement in GSM networks by reducing the number of home location register and visitor location register queries.
It is another object of the present invention to provide a method which reduces the processing requirement at the home location register and the mobile switching centers due to the removal of some of the send routing information and provide roaming number messages.
It is yet another object of the present invention to provide an improved method that allows the routing of calls from a gateway mobile switching center to a visiting mobile switching center without home location register and visitor location register queries.
It is still yet another object of the present invention to provide a method which reduces the signaling bandwidth requirements due to the reduction of the home location register and visitor location register queries for mobile terminated call setups.
The foregoing objects are achieved as is now described. A method and system for improving overall system capacity in GSM networks by reducing the number of home location register and visitor location register queries is disclosed. The method and system allows the reuse of the Mobile Subscriber Roaming Number (MSRN) by allocating the MSRN to a mobile terminal and using it for future calls. The method of the present invention allows the GMSC to cache the MSRN for a called mobile terminal. During a first call setup, an entry is recorded at a cache register that maps the Mobile Subscriber ISDN Number (MSISDN) of the mobile terminal to a previously allocated MSRN. Additionally, the Bearer Capability (BC) associated with this MSRN is also recorded in the cache register. When the next call arrives, the GMSC first checks if a MSRN for that called mobile terminal already exists in the cache register. If a cached MSRN is available and the BC associated with the cached MSRN matches the BC requested by the current call, then the GMSC uses the cached MSRN to route the call to the VMSC. The method and system of the present invention makes it unnecessary to query the HLR and VLR when a land-to-mobile call arrives thereby increasing network capacity while reducing processing load.
The above as well as additional objects, features, and advantages of the present invention will become apparent in the following detailed written description.